Once Alone
by RomaMarufixx
Summary: Mating season starts a relationship between two turtles. Turtlecest.
**Once Alone** by **RomaMarufixx**

 _Leo/Don, Raph/Mikey, mention of OT4_

This is turtlecest, don't like? Don't read!

All characters are over 18.

* * *

At almost half past one in the morning, Donnie saw a figure pass his lab door. He knew that the last member of his family had gone to bed around midnight, so the fact they were up and passing his lab, which was just near the entrance/exit of their home, meant that they were sneaking out.

Walking out of his lab he could hear Raph's snoring coming from the second floor so that ruled him out. Master Splinter had retired to bed early than all his sons as he had been feeling under the weather, and when Donnie checked in on him, he was sound asleep, not even noticing that his son had come to check on him, either that or he was pretending to sleep so that Donatello would not fuss over him. When Donnie passed Mikey's room he heard his brother murmuring in his sleep which meant that Leo was the turtle that had left the lair, which was confirmed when he found no one in his brother's room or the dojo.

After grabbing his bo from his lab, he made his way out of the lair, barely walking five steps before he saw a dark figure in front of him.

"It's unlike you to leave the lair this late at night without telling anyone." Donnie said as Leo moved forward so that he was visible. "Breaking one of your rules?" He teased.

"As are you, I thought we talked about you going to bed before the day changed into another?" Leo replied, raising a brow and Donnie sighed.

"I'll work my way into sleeping earlier, at least I'm not pulling any all nighters, besides I was about to go to bed when I noticed someone sneaking out and went to find out who it was and alas, here you are."

"Here I am." Leo repeated, his eyes fixed on his brother, making him slightly uncomfortable.

"What are you doing out here anyway, waiting for me?" Donnie asked, his heart beating slighter faster than usual because of the way his brother was still looking at him. Normally Donnie wouldn't have noticed how Leo was looking at him, it would have gone over his sleep deprived head, but he was on high alert since his and Leo's 'talk' the other day.

* * *

Donnie had noticed Leo acting very strange for a number of days now, like he was fighting an inner battle with himself. He'd also noticed the number of unusual looks that his eldest sibling had been directing his way, eying him like he was food. He had observed Leo's behaviour with Raph and Mikey as well, but he acted close to normal around their bright banded brothers. He could have also sworn that his brother was flirting with him the other day, he'd never been flirted with before but had seen such happen on television and was sure that was what happened between them.

Donnie never liked to see anyone struggle with anything, so as soon as Leo and he were alone, he'd tried to get out of him what was wrong, as well as finding out what it had to do with him.

"Leo?" he called out to his brother who was on the far side of the dojo meditating.

"What can I do for you Donatello?" His brother asked as he slowly came out of his meditative state.

"I was wondering if we could talk?"

"About?" Leo asked as he slowly stretched himself out before standing up.

"You." Donnie began as Leo finished his stretching. "I've noticed that you haven't really been yourself recently, I was wondering if something was wrong and if so, would you like to talk about it?" Donnie said, offering a friendly ear to his brother.

"Nothing is wrong Donatello."

"Are you sure, you know that I'm always here for you to talk to." Donnie said as his brother came closer to him.

"I know Donatello, but there is nothing wrong with me, I assure you." Leo said, resting a hand on his brother's shoulder, which he soon regretted. That few seconds of contact was enough to know that Leo's temperature was higher than it should be.

"Leo, have you got a temperature?" Donnie asked, pressing the back of his hand to Leo's forehead, he was very warm. A flurry of explanations for a raised temperature flew around in Donnie's head as he tried to diagnose his brother, it wasn't until the smell of incense drifted away and Donnie caught the other scent in the room that he knew what was wrong with his brother. "Leo, are you in...season?" He asked his brother who stepped away.

"No." Leo stated, his jaw almost locked. It would explain the strange behaviour, the stares and the flirting but even then Leo should be acting a lot worse, so Donnie deduce that Leo was trying to force himself under control.

"Leo, are you suppressing your instincts? You're going to make yourself sick!"

"And what do you expect me to do Donatello? Fuck you? Is that what you would like?" Leo said in a low, gravely voice, unlike his usual tone.

Donatello closed his eyes and counted to five to calm himself down and not act rashly like Leo seemed to want him to.

"I'd like to help you."

"There's not much you can do. Leo said as he stepped forward. "Aside from what I just offered." And then he left, brushing against his brother as he went.

* * *

"Yes, I knew it wouldn't take you long to follow me." Leo said in response to his brother's question. "I...I spoke to Master Splinter the other day."

"What about?" Donnie asked, not understanding where this conversation was going.

"About what happened between us the other day, about...what I said to you." Leo said, pausing for a second to gather his thoughts. "I was suppressing my natural instincts to mate and it was making me unwell and angry and I took it all out on you, I'm sorry that I made you worry and I'm sorry I was so vulgar towards you."

"You're always forgiven Leo, I just wish you could have come to me for help."

"I know that I should have but I thought that I could do this by myself, I almost did but then you confronted me." Leo smiled and Donnie laughed.

"So it's my fault you were rude to me? You just apologised to me."

"It appears my hormones still have yet to calm down." Leo said, taking a deep breath.

"Yet you're perfectly calm around our brothers." Donnie noted and Leo was glad for the dim lighting of the sewers as Donnie couldn't see him blush. "Why is that?"

"I wasn't sure at first, I thought that it was just the hormones identifying you as a...potential mate...but then I realised that I didn't see Raph or Mikey that way but it wasn't until my hormones started to calm that I realised why."

"And why is that?" Donnie asked trying to stop himself from grinning.

"I think that I have feelings for you...romantic feelings, as well as sexual." Leo confessed and Donnie burst into laughter causing Leo to blush further. "What are you laughing about?"

"Sorry." Donnie said trying to calm his laughter down. "But that was the worst love confession ever."

"Well it isn't exactly something that I've had to do before."

"Well, I could have done better." Donnie said, teasing his brother.

"And what would you have done?" Leo said, anger bubbling slightly, an emotion he experienced a great deal whilst going through his mating season.

"I love you Leonardo." Donnie said, in all seriousness and pressed in close to his brother, cupping his cheeks and pulling him into a deep kiss which lasted just over a minute before Donnie pulled away.

"That was a very good…" Leo said before clearing his throat to continue. "...confession."

"I told you I could have done it better." Donnie said before Leo pulled him into another kiss, and another, each one more heated than the last before Donnie put a temporary stop to them. "We shouldn't be doing this out here."

"Bedroom?" Leo asked, his eyes almost black with lust, their kissing stirring up his instincts to mate.

"The lab's soundproof." Donnie said and grinned when Leo churred and practically dragged him back into the lair.

* * *

As soon as the lab door clicked lock behind the, Leo threw Donnie up against the door as he aggressively kissed him. Donnie's nails dug into his brother's shoulders as Leo lifted him off the ground and they made their way over to the cot in one of the corners of the room.

Donnie's shell hit the bed and his arms wrapped around Leo's neck, pulling him down without breaking their kiss. Donnie could feel himself harden under his shell, but was reluctant to let himself drop down before his older brother, so he moved one of his hands, tracing it across Leo's shoulder and arm and then down his plastron to where a growing bulge was present.

Leo's churr broke the kiss as he dropped down and Donnie's hand fisted him, stroking him to his full hardness before letting himself drop down. As Donnie pumped Leo's erection, the older thrust his hips against his brother, his penis bumping against the other's exposed opening and after a while and some harder thrusts, that almost hurt, Donnie pushed Leo back.

"Leo we need lube." The genius gasped out and Leo looked at him with unfocused eyes, his instinct to mate almost taking over everything else. "In the draw." Donnie said, pointing to the nearest desk. Leo moved slowly across the room, his erection bobbing slightly as he reached the desk.

When he came back to the bed, the lid of the lube was off and one of his fingers was coated in it. He tensed up when he felt Leo's finger touch his backside but willed himself to calm down as Leo pushed his finger inside slowly. He soon added another finger, scissoring them as Donnie fisted his own erection and closed his eyes, enjoying himself.

Once Leo deemed Donatello ready he crawled on top of him and kissed him deeply as he pressed into his mate's body for the first time. Donnie moaned loudly, breaking their kiss as he gripped onto Leo's forearms to ground himself. His action caused Leo to pause, dragging his mouth over Donnie's and comfort him with his words and also with his hand until Donnie was ready for Leo to move, which he showed by changing their positions so that he was on top of his partner, his erection all the way in his brother, causing them both to moan.

Leo held out his hands for Donnie to hold and he laced their finger together for support whilst he began moving up and down on Leo's shaft, going faster with each rise and fall. Their grip on each other's hands loosened as their sweat from their lovemaking made them slippery and Donnie opted for using Leo's chest as leverage as Leo's hands gripped on tightly onto Donnie's thighs.

It didn't take much longer for Donnie to reach his climax, without either of them having touched his penis from the point of penetration. Once Donnie's orgasm subsided he was thrown onto his shell and Leo thrust in and out of his new mate until he reach his own orgasm, covering his mouth with Donnie's to muffled his cries of pleasure.

After a few minutes, Leo pulled off of his brother and collapsed by his side, his breathing starting to even out.

"How do you feel?" Donnie said, nuzzling his mate's neck and Leo answered by pulling his chin up and kissing him as passionately as when they first entered the room.

"I feel amazing….I also feel like lead." Leo chuckled and Donnie joined in with him. "I love you Donatello."

"I love you too Leonardo."

When Leo woke the next morning, the first thing he noticed was the clock nearest to him that read a little after eleven in the morning. He jumped out of the bed startling Donnie as he did so and began dressing himself with the gear that was scattered across the area close to the bed.

"Leo? What's wrong?"

"It's past eleven in the morning." Leo replied as he finished dressing.

"What?" Donnie replied, jumping off the bed, as shocked as Leo that they had slept passed their usually awakening time. Despite the amount of sleep that either of them good, neither of them slept passed six in the morning, and sometimes eight when it was a sunday once a month when they didn't have morning training.

When the two left the lab, they found Mikey and Raph sat on the couch playing a video game, barely looking at the two as they walked slowly towards them although Raph did have a smirk on his face. When the blue and purple banded turtle's stood behind the coach their brothers were sat on they were at a loss of what to say and look each other for help.

"Raph-" Leo began to speak to his brother but was cut off.

"We thought you too should deserve to sleep in, I mean you didn't get to bed until late." Raph said, his grin getting wider.

"How do you know what time we went to bed?" Donnie asked, flushing slightly.

"Well you guys were loud and then you slammed the door, we got the jist of what was happening and I would say you went to bed around half an hour after that, give or take." Miley explained, grinning as wide as Raph's was.

"We-" Leo began to say and sighed angrily when Raphael cut him off again.

"Yeah, it took you two long enough, what was wrong Leo? Didn't wanna give in?" Raph said, pausing the game so that he could look behind at his brother with a cocky look on his features. "Gotta give it to ya' bro' I didn't even last a day before I was all over Mikey." He confessed and both Donnie and Leo turned to their youngest brother with shocked looks on their faces.

"What? Just because we keep things more private than you too doesn't mean we don't do it." Mikey said, continuing the game whilst Raph was distracted so he'd win.

"Hey, cheat!" Raph exclaimed, pushing Mikey's shoulder while the other laughed.

"So you two are…?" Leo questioned, looking between the two.

"Yeah we are, have been for a while now, Master Splinter's fine with it, he was just waiting for ya to go to Donnie."

"He was getting kinda worried you were gonna cause yourself to pass out." Mikey said. "With you trying to ignore your feelings and stuff, that can't have felt good." He grimaced.

"I spoke to Master Splinter…"

"Yeah, he told us about that the other day and ask us to keep an eye on you to make sure you didn't go any further...unless of course Donnie wanted you too." Mikey winked at his elder brothers.

"You've been stalking us?" Donnie asked.

"Surprised you didn't notice it, shows how out of it both of ya' were." Raph said, staring at Leo, almost in competition.

"I wasn't out of it?"

"You so were dude, you didn't even realise it." Mikey said and then spun around so that he was kneeling on the couch and facing his brothers. "So you guys up for a four way?" He smiled brightly, taking Leo and Don aback and causing Raph to hit him upside the head.

"Shut up Mikey ya' spooking 'em."

"I was only teasing! Look at their faces!" Mikey laughed at his brothers expenses.

The joking aside both Leo and Donnie were happy that their relationship was accepted by their brothers and their father, although they would still have to talk to their father about their new found love and what that meant for their family, but they knew that this was the start of something better, a new light in their mostly dark lives.


End file.
